Gerald F. Giesbrecht

A Latent Variable Approach to Determining the Structure of Executive Function in Preschool Children

The composition of executive function (EF) in preschool children was examined using confirmatory factor analysis (CFA). A sample of 129 children between 3 and 5 years of age completed a battery of EF tasks. Using performance indicators of working memory and inhibition similar to previous CFA studies with preschoolers, we replicated a unitary EF factor structure. Next, additional performance indicators were included to distinctly measure working memory, set shifting, and inhibition factors. A two-factor model consisting of working memory and inhibition fit the data better than both a single-factor model and a three-factor model. Findings suggest that the structure of EF in preschoolers that emerges from CFA is influenced by task and performance indicator selection.

Child and context characteristics in trajectories of physical and relational victimization among early elementary school children

Transactional models suggest that peer victimization results from both individual and context differences, and understanding these differences may point to important targets for prevention and interventions that reduce victimization. Multilevel modeling was used to examine within-person (aggression and emotional dysregulation), between-person (sex and age), and between-school (participation in a victimization prevention program) factors that influence changes in physical and relational victimization over the first three years of elementary school. Children (n = 423) reported their experiences of peer victimization at entry into Grade 1 and at the end of Grade 1, Grade 2, and Grade 3. On average, trajectories of both physical and relational victimization declined. However, for individual children, teacher-rated aggression was associated with increases in physical and relational victimization, while emotional dysregulation was associated with attenuation of longitudinal declines in physical victimization and increases in relational victimization. Individual differences in sex and age at entry into Grade 1 did not significantly influence victimization trajectories over Grades 1 to 3. Children who participated in the WITS® victimization prevention program showed significant declines in physical and relational victimization. Levels of victimization among nonparticipants remained stable. Implications of child and context characteristics for preventing peer victimization in elementary school are discussed.

Methodological and Epistemological Issues in the Interpretation of Infant Cognitive Development

This commentary on J. Kagan (2008) addresses 2 issues. The first concerns the importance of studying developmental sequences and processes of change. The second concerns epistemological differences between contemporary neonativist approaches and classical theories of development. The commentary argues that classical theories of infant cognition and contemporary neonativist theories fundamentally differ in terms of how they conceptualize the workings of the mind. These differences affect the meaning of terms such as representation and reasoning. Also discussed are implications of epistemological differences for developmental explanations. The commentary concludes that epistemological differences must be articulated more fully in order to improve understanding of different theories and in order to evaluate the relative merits and shortcomings of those theories.

Psychological Models of Time: Arrows, Cycles and Spirals

This article examines the models of time presented by Yamada and Kato (2006) and Rudolph (2006). Although we agree with Yamada and Kato that the subjective experience of time is not linear and homogeneous, we argue that cyclical models of time are not good models of representing normative ontogenetic development. We also critically examine Rudolph’s suggestion that the experience of time is derived from a succession of discrete acts of attention and ‘states of ambivalence’ that interpolate between the discrete acts of attention.

Vitamin D Deficiency and Antenatal and Postpartum Depression: A Systematic Review

Vitamin D has been implicated in antenatal depression (AD) and postpartum depression (PPD) in many studies; however, results have been inconsistent due to the complexity of this association. We searched the MEDLINE, Embase, PsycINFO, and Maternity and Infant Care databases for literature addressing associations between vitamin D and AD and PPD. Two independent authors reviewed titles and abstracts of the search results and selected studies for full review. Data were extracted, and a quality rating was done using the Newcastle–Ottawa Scale (NOS) on the selected studies. A total of 239 studies were identified; 14 were included in the review. The quality assessment of the included studies ranged from moderate to high. Of the studies on PPD, five of nine (55%) showed a significant association between vitamin D and PPD. Five of seven (71%) studies on AD showed a significant association with vitamin D status. As the included studies used different effect estimates and statistical analyses to report the association, it was not possible to transform the existing data into one single effect measure to employ meta-analytic techniques. While results of this systematic review vary, they indicate a significant association between vitamin D status and AD and PD.